Bessho 





where M(x,y,z) = -M(x,y,z), then has no radiating wave. Hence, putting the 

 above into the first equation, we have 



Tr(x,y.-0) = -P(x.y) = ^_ 





r2 —\ m(x,y) 



21 

 Bx" 



2 O 



^■■ 



m(x,y) , 



where m(x,y) = M(x,y,-0). By the assumption, this is a wave-free pressure 

 distribution. 



792 



